The ASP.NET AJAX Interview Questions contains the most frequently asked questions in ASP.NET AJAX. These lists of questions will gauge your familiarity with the ASP.NET AJAX platform.
What is Ajax?
The term Ajax was coined by Jesse James Garrett and is a short form for "Asynchronous Javascript and XML". Ajax represents a set of commonly used techniques, like HTML/XHTML, CSS, Document Object Model(DOM), XML/XSLT, Javascript and the XMLHttpRequest object, to create RIA's (Rich Internet Applications).
Ajax gives the user, the ability to dynamically and asynchronously interact with a web server, without using a plug-in or without compromising on the user’s ability to interact with the page. This is possible due to an object found in browsers called the XMLHttpRequest object.
What is ASP.NET AJAX?
‘ASP.NET AJAX’ is a terminology coined by Microsoft for ‘their’ implementation of AJAX, which is a set of extensions to ASP.NET. These components allow you to build rich AJAX enabled web applications, which consists of both server side and client side libraries.
Which is the current version of ASP.NET AJAX Control Toolkit?
As of this writing, the toolkit version is Version 1.0.20229 (if you are targeting Framework 2.0, ASP.NET AJAX 1.0 and Visual Studio 2005) and Version 3.0.20229 (if targeting .NET Framework 3.5 and Visual Studio 2008).
What role does the ScriptManager play?
The ScriptManager manages all ASP.NET AJAX resources on a page and renders the links for the ASP.NET AJAX client libraries, which lets you use AJAX functionality like PageMethods, UpdatePanels etc. It creates the PageRequestManager and Application objects, which are prominent in raising events during the client life cycle of an ASP.NET AJAX Web page. It also helps you create proxies to call web services asynchronously.
Can we use multiple ScriptManager on a page?
No. You can use only one ScriptManager on a page.
What is the role of a ScriptManagerProxy?
A page can contain only one ScriptManager control. If you have a Master-Content page scenario in your application and the MasterPage contains a ScriptManager control, then you can use the ScriptManagerProxy control to add scripts to content pages.
Also, if you come across a scenario where only a few pages in your application need to register to a script or a web service, then its best to remove them from the ScriptManager control and add them to individual pages, by using the ScriptManagerProxy control. That is because if you added the scripts using the ScriptManager on the Master Page, then these items will be downloaded on each page that derives from the MasterPage, even if they are not needed, which would lead to a waste of resources.
What are the requirements to run ASP.NET AJAX applications on a server?
You would need to install ‘ASP.NET AJAX Extensions’ on your server. If you are using the ASP.NET AJAX Control toolkit, then you would also need to add the AjaxControlToolkit.dll in the /Bin folder.
Note: ASP.NET AJAX 1.0 was available as a separate downloadable add-on for ASP.NET 2.0. With ASP.NET 3.5, the AJAX components have been integrated into ASP.NET.
Explain the UpdatePanel?
The UpdatePanel enables you to add AJAX functionality to existing ASP.NET applications. It can be used to update content in a page by using Partial-page rendering. By using Partial-page rendering, you can refresh only a selected part of the page instead of refreshing the whole page with a postback.
Can I use ASP.NET AJAX with any other technology apart from ASP.NET?
To answer this question, check out this example of using ASP.NET AJAX with PHP, to demonstrate running ASP.NET AJAX outside of ASP.NET. Client-Side ASP.NET AJAX framework can be used with PHP and Coldfusion.
How can you cancel an Asynchronous postback?
Yes you can. Read my article over here.
Difference between Server-Side AJAX framework and Client-side AJAX framework?
ASP.NET AJAX contains both a server-side Ajax framework and a client-side Ajax framework. The server-side framework provides developers with an easy way to implement Ajax functionality, without having to possess much knowledge of JavaScript. The framework includes server controls and components and the drag and drop functionality. This framework is usually preferred when you need to quickly ajaxify an asp.net application. The disadvantage is that you still need a round trip to the server to perform a client-side action.
The Client-Side Framework allows you to build web applications with rich user-interactivity as that of a desktop application. It contains a set of JavaScript libraries, which is independent from ASP.NET. The library is getting rich in functionality with every new build released.
How can you debug ASP.NET AJAX applications?
Explain about two tools useful for debugging: Fiddler for IE and Firebug for Mozilla.
Can we call Server-Side code (C# or VB.NET code) from javascript?
Yes. You can do so using PageMethods in ASP.NET AJAX or using webservices.
Can you nest UpdatePanel within each other?
Yes, you can do that. You would want to nest update panels to basically have more control over the Page Refresh.
How can you to add JavaScript to a page when performing an asynchronous postback?
Use the ScriptManager class. This class contains several methods like the RegisterStartupScript(), RegisterClientScriptBlock(), RegisterClientScriptInclude(), RegisterArrayDeclaration(),RegisterClientScriptResource(), RegisterExpandoAttribute(), RegisterOnSubmitStatement() which helps to add javascript while performing an asynchronous postback.
Explain differences between the page execution lifecycle of an ASP.NET page and an ASP.NET AJAX page?
In an asynchronous model, all the server side events occur, as they do in a synchronous model. The Microsoft AJAX Library also raises client side events. However when the page is rendered, asynchronous postback renders only the contents of the update panel, where as in a synchronous postback, the entire page is recreated and sent back to the browser.
Explain the AJAX Client life-cycle events
Here’s a good article about the same.
Is the ASP.NET AJAX Control Toolkit(AjaxControlToolkit.dll) installed in the Global Assembly Cache?
No. You must copy the AjaxControlToolkit.dll assembly to the /Bin folder in your application.
Those were some frequently asked questions you should have knowledge about. In one of the coming articles, we will cover some more ASP.NET AJAX FAQ’s which were not covered in this article. I hope this article was useful and I thank you for viewing it.
17. In the Design view in Visual Studio 2005 of an ASP.NET web page, what is the easiest way to create an event handler for the default event of a ASP.NET server control?
A. Open the code-behind page and write the code.
B. Right-click the control and select Create Handler.
C. Drag an event handler from the ToolBox to the desired control.
D. Double-click the control.
18. Which of the following represents the best use of the Table, TableRow, and Table-Cell controls?
A. To create and populate a Table in Design view
B. To create a customized control that needs to display data in a tabular fashion
C. To create and populate a Table with images
D. To display a tabular result set
19. For your ASP.NET web application your graphics designer created elaborate images that show the product lines of your company. Some of graphics of the product line are rectangular, circular, and others are having complex shapes. You need to use these images as a menu on your Web site. What is the best way of incorporating these images into your Web site?
A. Use ImageButton and use the x- and y-coordinates that are returned when the user clicks to figure out what product line the user clicked.
B. Use the Table, TableRow, and TableCell controls, break the image into pieces that are displayed in the cells, and use the TableCell control’s Click event to identify the product line that was clicked.
C. Use the MultiView control and break up the image into pieces that can be displayed in each View control for each product line. Use the Click event of the View to identify the product line that was clicked.
D. Use an ImageMap control and define hot spot areas for each of the product lines. Use the PostBackValue to identify the product line that was clicked.
20. You are writing ASP.NET 2.0 Web site that collects lots of data from users, and the data collection forms spreads over multiple ASP.NET Web pages. When the user reaches the last page, you need to gather all of data, validate the data, and save the data to the SQL Server database. You have noticed that it can be rather difficult to gather the data that is spread over multiple pages and you want to simplify this application. What is the easiest control to implement that can be used to collect the data on a single Web page?
A. The View control
B. The TextBox control
C. The Wizard control
D. The DataCollection control
21. In your ASP.NET 2.0 web application you want to display an image that is selected from a collection of images. What approach will you use to implementing this?
A. Use the ImageMap control and randomly select a HotSpot to show or hide.
B. Use the Image control to hold the image and a Calendar control to randomly select a date for each image to be displayed.
C. Use the AdServer control and create an XML file with configuration of the control.
D. Use an ImageButton control to predict randomness of the image to be loaded based on the clicks of the control.
22. In your ASP.NET web application you want to display a list of clients on a Web page. The client list displays 10 clients at a time, and you require the ability to edit the clients. Which Web control is the best choice for this scenario?
A. The DetailsView control
B. The Table control
C. The GridView control
D. The FormView control
23. While developing ASP.NET 2.0 web application you want to display a list of parts in a master/detail scenario where the user can select a part number using a list that takes a minimum amount of space on the Web page. When the part is selected, a DetailsView control displays all the information about the part and allows the user to edit the part. Which Web control is the best choice to display the part number list for this scenario?
A. The DropDownList control
B. The RadioButtonList control
C. The FormView control
D. The TextBox control
17. In the Design view in Visual Studio 2005 of an ASP.NET web page, what is the easiest way to create an event handler for the default event of a ASP.NET server control? A. Open the code-behind page and write the code. B. Right-click the control and select Create Handler. C. Drag an event handler from the ToolBox to the desired control.D. Double-click the control.
18. Which of the following represents the best use of the Table, TableRow, and Table-Cell controls?A. To create and populate a Table in Design view B. To create a customized control that needs to display data in a tabular fashionC. To create and populate a Table with images D. To display a tabular result set
19. For your ASP.NET web application your graphics designer created elaborate images that show the product lines of your company. Some of graphics of the product line are rectangular, circular, and others are having complex shapes. You need to use these images as a menu on your Web site. What is the best way of incorporating these images into your Web site? A. Use ImageButton and use the x- and y-coordinates that are returned when the user clicks to figure out what product line the user clicked. B. Use the Table, TableRow, and TableCell controls, break the image into pieces that are displayed in the cells, and use the TableCell control’s Click event to identify the product line that was clicked. C. Use the MultiView control and break up the image into pieces that can be displayed in each View control for each product line. Use the Click event of the View to identify the product line that was clicked. D. Use an ImageMap control and define hot spot areas for each of the product lines. Use the PostBackValue to identify the product line that was clicked.
20. You are writing ASP.NET 2.0 Web site that collects lots of data from users, and the data collection forms spreads over multiple ASP.NET Web pages. When the user reaches the last page, you need to gather all of data, validate the data, and save the data to the SQL Server database. You have noticed that it can be rather difficult to gather the data that is spread over multiple pages and you want to simplify this application. What is the easiest control to implement that can be used to collect the data on a single Web page? A. The View control B. The TextBox control C. The Wizard control D. The DataCollection control
21. In your ASP.NET 2.0 web application you want to display an image that is selected from a collection of images. What approach will you use to implementing this? A. Use the ImageMap control and randomly select a HotSpot to show or hide. B. Use the Image control to hold the image and a Calendar control to randomly select a date for each image to be displayed. C. Use the AdServer control and create an XML file with configuration of the control. D. Use an ImageButton control to predict randomness of the image to be loaded based on the clicks of the control.
22. In your ASP.NET web application you want to display a list of clients on a Web page. The client list displays 10 clients at a time, and you require the ability to edit the clients. Which Web control is the best choice for this scenario? A. The DetailsView control B. The Table control C. The GridView control D. The FormView control
23. While developing ASP.NET 2.0 web application you want to display a list of parts in a master/detail scenario where the user can select a part number using a list that takes a minimum amount of space on the Web page. When the part is selected, a DetailsView control displays all the information about the part and allows the user to edit the part. Which Web control is the best choice to display the part number list for this scenario? A. The DropDownList control B. The RadioButtonList control C. The FormView control D. The TextBox control
9. How will you identify which event in the ASP.NET Web page life cycle takes the longest time to execute?
A. Turn on ASP.NET trace and run the Web application.
B. Add a few code to each of the page life-cycle events that will print the current time.
C. In the Web.config file, add the monitorTimings attribute and set it to True.
D. In the Web site properties, turn on the performance monitor and run the Web application. After that, open performance monitor to see the timings.
11. You are interested in examining the data that is posted to the Web server. What trace result section can you use to see this information?
A. Control Tree
B. Headers Collection
C. Form Collection
D. Server Variables
12. While creating web site you need to add an HTML Web server control to the Web page, you need to drag an HTML element from the ToolBox of Visual Studio 2005 to the Web page and then which of the following tasks you will perform?
A. Right-click the HTML element and click Run=Server.
B. Double-click the HTML element to convert it to an HTML server control.
C. Right-click the HTML element and click Run As Server Control.
D. Click the HTML element and set ServerControl to true in the Properties window.
13. While testing your ASP.NET web application you noticed that while clicking on CheckBox of one of the web page it does not cause a PostBack; you required that the CheckBox should make PostBack so Web page can be update on the server-side code. How can you make the CheckBox to cause a PostBack?
A. Set the AutoPostBack property to true.
B. Add JavaScript code to call the ForcePostBack method.
C. Set the PostBackAll property of the Web page to true.
D. Add server-side code to listen for the click event from the client.
14. While writing code in Visual Studio 2005 you creates a new instance of a ASP.NET TextBox server control, what do you need to do to get the TextBox to display on the Web page?
A. Call the ShowControl method on the TextBox.
B. Set the VisibleControl to true on the TextBox.
C. Add the TextBox instance to the form1.Controls collection.
D. Execute the AddControl method on the Web page.
15. While creating your ASP.NET web based application you want to create multiple RadioButton server controls which should be mutually exclusive, what property of RadioButton server controls you must set?
A. Exclusive
B. MutuallyExclusive
C. Grouped
D. GroupName
16. While creating an ASP.NET web application with the help of Visual Studio 2005 you are creates a Web page that has several related buttons, such as fast-forward, reverse, play, stop, and pause. There should be one event handler that handles the processes of PostBack from these Button server controls. Other than the normal Submit button, what type of button can you create?
A. OneToMany
B. Command
C. Reset
D. ManyToOne
9. How will you identify which event in the ASP.NET Web page life cycle takes the longest time to execute? A. Turn on ASP.NET trace and run the Web application. B. Add a few code to each of the page life-cycle events that will print the current time. C. In the Web.config file, add the monitorTimings attribute and set it to True. D. In the Web site properties, turn on the performance monitor and run the Web application. After that, open performance monitor to see the timings.
11. You are interested in examining the data that is posted to the Web server. What trace result section can you use to see this information?A. Control Tree B. Headers Collection C. Form Collection D. Server Variables
12. While creating web site you need to add an HTML Web server control to the Web page, you need to drag an HTML element from the ToolBox of Visual Studio 2005 to the Web page and then which of the following tasks you will perform? A. Right-click the HTML element and click Run=Server. B. Double-click the HTML element to convert it to an HTML server control. C. Right-click the HTML element and click Run As Server Control. D. Click the HTML element and set ServerControl to true in the Properties window.
13. While testing your ASP.NET web application you noticed that while clicking on CheckBox of one of the web page it does not cause a PostBack; you required that the CheckBox should make PostBack so Web page can be update on the server-side code. How can you make the CheckBox to cause a PostBack? A. Set the AutoPostBack property to true. B. Add JavaScript code to call the ForcePostBack method. C. Set the PostBackAll property of the Web page to true. D. Add server-side code to listen for the click event from the client.
14. While writing code in Visual Studio 2005 you creates a new instance of a ASP.NET TextBox server control, what do you need to do to get the TextBox to display on the Web page? A. Call the ShowControl method on the TextBox. B. Set the VisibleControl to true on the TextBox. C. Add the TextBox instance to the form1.Controls collection. D. Execute the AddControl method on the Web page.
15. While creating your ASP.NET web based application you want to create multiple RadioButton server controls which should be mutually exclusive, what property of RadioButton server controls you must set? A. Exclusive B. MutuallyExclusive C. Grouped D. GroupName
16. While creating an ASP.NET web application with the help of Visual Studio 2005 you are creates a Web page that has several related buttons, such as fast-forward, reverse, play, stop, and pause. There should be one event handler that handles the processes of PostBack from these Button server controls. Other than the normal Submit button, what type of button can you create? A. OneToMany B. Command C. Reset D. ManyToOne
1. What is the name of the property of ASP.NET page that you can query to determine that a ASP.NET page is being requested not data being submitted to web server?
A. FirstGet
B. Initialized
C. IncludesData
D. IsPostBack
IsPostBack
2. While creating a Web site with the help of Visual Studio 2005 on a remote computer that does not have Front Page Server Extensions installed, which Web site type will you create in Visual Studio 2005?
A. Remote HTTP
B. File
C. FTP
D. Local HTTP
Hypertext Transfer Protocol (HTTP)
3. If you want to create a new Web site with the help of Visual Studio 2005 on a Web server that is hosted by your ISP (Internet Services provider) and the Web server has Front Page Server Extensions installed, what type of Web site type would you create in Visual Studio 2005?
A. Local HTTP
B. File
C. FTP
D. Remote HTTP
Hypertext Transfer Protocol (HTTP)
4. For separating server-side code from client-side code on a ASP.NET page, what programming model should you use?
A. Separation model
B. Code-Behind model
C. In-Line model
D. ClientServer model
5. Amit created a new Web site using Visual Studio 2005 in programming language C#. Later, Amit received an existing Web page from his boss, which consisted of the Contact.aspx file with the Contact.aspx.vb code-behind page. What must Amit do to use these files?
A. Amit can simply add the files Contact.aspx, Contact.aspx.vb into the existing Web site, because ASP.NET 2.0 supports Web sites that have Web pages that were programmed with different languages.
B. The Contact.aspx file will work, but Amit must rewrite the code-behind page using C#.
C. Both files Contact.aspx and Contact.aspx.vb must be rewritten in C#.
D. Amit must create a new Web site that contains these files Contact.aspx and Contact.aspx.vb. Set a Web reference to the new site.
6. If you want to make a configuration setting change in your server that will affect to all Web and Windows applications on the current machine. Where you will make the changes?
A. Global.asax
B. Web.config
C. Machine.config
D. Global.asax
7. If you want to make a configuration setting change that will affect only the current Web application. Which file will you change?
A. Web.config that is in the same folder as the Machine.config file
B. Web.config in the root of the Web application
C. Machine.config
D. Global.asax
8. For making a configuration setting change that will affect only the current Web application. Is there any tool that has a user-friendly Graphical User Interface (GUI)?
A. The Microsoft Management Utility
B. Microsoft Word
C. Visual Studio, using the Tools > Options path
D. Web Site Administration Tool
1. What is the name of the property of ASP.NET page that you can query to determine that a ASP.NET page is being requested not data being submitted to web server? A. FirstGet B. Initialized C. IncludesData D. IsPostBack
IsPostBack
2. While creating a Web site with the help of Visual Studio 2005 on a remote computer that does not have Front Page Server Extensions installed, which Web site type will you create in Visual Studio 2005? A. Remote HTTP B. File C. FTP D. Local HTTP
Hypertext Transfer Protocol (HTTP)
3. If you want to create a new Web site with the help of Visual Studio 2005 on a Web server that is hosted by your ISP (Internet Services provider) and the Web server has Front Page Server Extensions installed, what type of Web site type would you create in Visual Studio 2005? A. Local HTTP B. File C. FTP D. Remote HTTP
Hypertext Transfer Protocol (HTTP)
4. For separating server-side code from client-side code on a ASP.NET page, what programming model should you use? A. Separation model B. Code-Behind model C. In-Line model D. ClientServer model
5. Amit created a new Web site using Visual Studio 2005 in programming language C#. Later, Amit received an existing Web page from his boss, which consisted of the Contact.aspx file with the Contact.aspx.vb code-behind page. What must Amit do to use these files? A. Amit can simply add the files Contact.aspx, Contact.aspx.vb into the existing Web site, because ASP.NET 2.0 supports Web sites that have Web pages that were programmed with different languages. B. The Contact.aspx file will work, but Amit must rewrite the code-behind page using C#. C. Both files Contact.aspx and Contact.aspx.vb must be rewritten in C#. D. Amit must create a new Web site that contains these files Contact.aspx and Contact.aspx.vb. Set a Web reference to the new site.
6. If you want to make a configuration setting change in your server that will affect to all Web and Windows applications on the current machine. Where you will make the changes? A. Global.asax B. Web.config C. Machine.config D. Global.asax
7. If you want to make a configuration setting change that will affect only the current Web application. Which file will you change? A. Web.config that is in the same folder as the Machine.config file B. Web.config in the root of the Web application C. Machine.config D. Global.asax
8. For making a configuration setting change that will affect only the current Web application. Is there any tool that has a user-friendly Graphical User Interface (GUI)? A. The Microsoft Management Utility B. Microsoft Word C. Visual Studio, using the Tools > Options path D. Web Site Administration Tool
